Add day 12 solution

day-14/day-14.py

@@ -0,0 +1,73 @@
+#!/usr/bin/env python3
+from pathlib import Path
+from collections import Counter, defaultdict
+
+
+def part_1(input):
+    result = 0
+    template = input.pop(0).strip()
+    input.pop(0)
+    rules = {k.strip(): v.strip()
+             for line in input for k, v in [line.strip().split('->')]}
+    counts = defaultdict(int)
+    for i in range(len(template) - 1):
+        counts[template[i: i + 2]] += 1
+    for _ in range(10):
+        tmp_cnts = counts.copy()
+        for k in tmp_cnts:
+            if k in rules:
+                c = tmp_cnts[k]
+                counts[k] -= c
+                counts[k[0] + rules[k]] += c
+                counts[rules[k] + k[1]] += c
+    char_counts = defaultdict(int)
+    for k in counts:
+        char_counts[k[0]] += counts[k]
+        char_counts[k[1]] += counts[k]
+    char_counts[template[0]] += 1
+    char_counts[template[-1]] += 1
+    for k in char_counts:
+        char_counts[k] //= 2
+    char_counts = sorted(char_counts.items(),
+                         key=lambda kv: kv[1])
+    result = char_counts[-1][1] - char_counts[0][1]
+    print("Part 1 result:", result)
+
+
+def part_2(input):
+    result = 0
+    template = input.pop(0).strip()
+    input.pop(0)
+    rules = {k.strip(): v.strip()
+             for line in input for k, v in [line.strip().split('->')]}
+    counts = defaultdict(int)
+    for i in range(len(template) - 1):
+        counts[template[i: i + 2]] += 1
+    for _ in range(40):
+        tmp_cnts = counts.copy()
+        for k in tmp_cnts:
+            if k in rules:
+                c = tmp_cnts[k]
+                counts[k] -= c
+                counts[k[0] + rules[k]] += c
+                counts[rules[k] + k[1]] += c
+    char_counts = defaultdict(int)
+    for k in counts:
+        char_counts[k[0]] += counts[k]
+        char_counts[k[1]] += counts[k]
+    char_counts[template[0]] += 1
+    char_counts[template[-1]] += 1
+    for k in char_counts:
+        char_counts[k] //= 2
+    char_counts = sorted(char_counts.items(),
+                         key=lambda kv: kv[1])
+    result = char_counts[-1][1] - char_counts[0][1]
+    print("Part 2 result:", result)
+
+
+input = list()
+p = Path(__file__).with_name('input.txt')
+with open(p) as f:
+    input = f.readlines()
+    part_1(input.copy())
+    part_2(input.copy())

day-14/input.txt

@@ -0,0 +1,102 @@
+NCOPHKVONVPNSKSHBNPF
+
+ON -> C
+CK -> H
+HC -> B
+NP -> S
+NH -> H
+CB -> C
+BB -> H
+BC -> H
+NN -> C
+OH -> B
+SF -> V
+PB -> H
+CP -> P
+BN -> O
+NB -> B
+KB -> P
+PV -> F
+SH -> V
+KP -> S
+OF -> K
+BS -> V
+PF -> O
+BK -> S
+FB -> B
+SV -> B
+BH -> V
+VK -> N
+CS -> V
+FV -> F
+HS -> C
+KK -> O
+SP -> N
+FK -> B
+CF -> C
+HP -> F
+BF -> O
+KC -> C
+VP -> O
+BP -> P
+FF -> V
+NO -> C
+HK -> C
+HV -> B
+PK -> P
+OV -> F
+VN -> H
+PC -> K
+SB -> H
+VO -> V
+BV -> K
+NC -> H
+OB -> S
+SN -> B
+HF -> P
+VF -> B
+HN -> H
+KS -> S
+SC -> S
+CV -> B
+NS -> P
+KO -> V
+FS -> O
+PH -> K
+BO -> C
+FH -> B
+CO -> O
+FO -> F
+VV -> N
+CH -> V
+NK -> N
+PO -> K
+OK -> K
+PP -> O
+OC -> P
+FC -> N
+VH -> S
+PN -> C
+VB -> C
+VS -> P
+HO -> F
+OP -> S
+HB -> N
+CC -> K
+KN -> S
+SK -> C
+OS -> N
+KH -> B
+FP -> S
+NF -> S
+CN -> S
+KF -> C
+SS -> C
+SO -> S
+NV -> O
+FN -> B
+PS -> S
+HH -> C
+VC -> S
+OO -> C
+KV -> P